1. Field of the Invention
The present invention relates to an optical switch.
2. Description of the Related Art
An optical switch, such as a multiplexer, is disclosed in the specification of the U.S. Pat. No. 6,657,770. In this optical switch, light beams output from a fiber array are converted into parallel beams in a micro-lens array and then led to an optical system arranged at a later stage. The parallel beams are expanded using two lenses, as shown in FIG. 5, for instance, led to a dispersive element, and subsequently concentrated and led to a mirror array.
In the optical switch disclosed in the specification of the U.S. Pat. No. 6,657,770, light emitted from the input/output port must be rendered parallel by the lens array, then concentrated using various kinds of optical elements into the deflection unit, and must again be returned to the input/output port. Downsizing of the optical switch is difficult in this configuration. Moreover, quality degradation may occur because of the sum total of the properties of various optical elements and the adjustment error. Moreover, a drawback namely, the larger the number of optical elements, the greater is the deviation from the ideal condition, cannot be avoided.